p–n Heterojunction formation in polyaniline–SnO2 organic–inorganic hybrid composite materials leading to enhancement in sensor functionality toward benzene and toluene vapors at room temperature

Organic–inorganic hybrid composite (OIHC) materials were synthesized through physical grinding of conducting p-polyaniline and n-SnO2 with different weight %. Characterization by FT-IR, XRD, SEM and AC impedance studies revealed a mutual interaction and formation of p–n heterojunctions. In N2 atmosphere OIHC materials had enhancement in sensor functionality toward benzene and toluene vapors at room temperature. Good correlation existed between number of p–n heterojunctions and sensor efficiencies. An optimized material with 40 wt% SnO2 showed 10% sensor efficiency for benzene and slightly higher value for toluene. Considering weak/nil interaction of analyte, the present work produced fairly efficient hybrid sensor materials from almost insensitive organic and inorganic components.